High molecular weight polyacrylates for aluminum protection in warewash applications

ABSTRACT

A warewashing detergent composition is provided for use for in cleaning of alkaline sensitive metals such as aluminum or aluminum containing alloys. The compositions include alternatives to sodium tripolyphosphate and/or other phosphorous containing raw materials, while retaining cleaning performance and corrosion prevention. According to the invention, high molecular weight polyacrylates (polyacrylic acid homopolymers) with a molecular weight of at least about 5000 are used as corrosion inhibitors and can be included for aluminum protection in a number of different detergent compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation application of U.S. Ser. No. 12/869,815 filedAug. 27, 2010, now Pat. No. 8,691,018 issued on Apr. 8, 2014, hereinincorporated by refernce in its entirety.

FIELD OF THE INVENTION

The invention relates to corrosion inhibiting compositions and detergentand cleaning compositions incorporating the same, particularlywarewashing compositions comprising polyacrylates (or polyacrylic acid),and their use for cleaning of alkaline sensitive metals such as aluminumor aluminum containing alloys.

BACKGROUND OF THE INVENTION

In recent years there has been an ever increasing trend towards saferand sustainable detergent compositions. This has led to the developmentof alternative complexing agents, builders, threshold agents, corrosioninhibitors, and the like, which are used instead of predominantlyphosphorous containing compounds. Phosphates can bind calcium andmagnesium ions, provide alkalinity, act as threshold agents, and protectalkaline sensitive metals such as aluminum and aluminum containingalloys.

Other corrosion inhibitors include silicates, such as, sodium silicate.Sodium silicate has a tendency to begin precipitating from aqueoussolution at a pH below 11, thus reducing its effectiveness to preventcorrosion of the contacted surfaces when used in cleaning solutionshaving a lower pH. Additionally, when allowed to dry on a surfacesilicates form films and/or spots which are visible and themselves arevery difficult to remove. The presence of these silicon containingdeposits can affect the texture, appearance and on cooking or storagesurfaces the taste of the materials that come into contact with thecleaned surfaces.

It is an object of the invention to address at least one of the aboveproblems and/or to offer detergent compositions with usage and/orenvironmental benefits.

SUMMARY OF THE INVENTION

The discovery that using high molecular weight polyacrylates, namelythose with molecular weights of 5000 or above and ideally those withmolecular weights of 10,000 or above, can achieve corrosion protectionfor Aluminum and aluminum containing alloys.

In one embodiment, the present invention relates to a corrosioninhibiting composition that may be used in formulation of detergents,cleaning compositions, and in protecting aluminum and aluminumcontaining alloys from corrosion. The corrosion inhibiting compositioncomprises the use of high molecular weight polyacrylates, (orpolyacrylic acid homopolymers). The polyacrylates (or polyacrylic acidhomopolymer) or combination of the same preferably includes those with amolecular weight of 5000 or above, more preferably, 10,000 or above.According to the invention, these high molecular weight polymers achievecorrosion inhibition and cleaning in detergent compositions without theneed for phosphorous containing components.

In one embodiment a detergent composition is provided according to theinvention. A detergent composition including an alkalinity source, andat least one high molecular weight polyacrylate (or polyacrylic acidhomopolyer) for corrosion inhibition. The cleaning agent also preferablyincludes a detersive amount of a surfactant. The alkaline source can beprovided in an amount effective to provide a use composition having a pHof at least about 8 . The high molecular weight polyacrylate (orpolyacrylic acid homopolymer) is provided in an amount sufficient toreduce corrosion of aluminum and/or aluminum containing alloys at a pHof about 8 or greater.

Articles which require such cleaning according to the invention includesany article with a surface that contains an alkaline sensitive metal,such as, aluminum or aluminum containing alloys. Such articles can befound in industrial plants, maintenance and repair services,manufacturing facilities, kitchens, and restaurants. Exemplary equipmenthaving a surface containing an alkaline sensitive metals include sinks,cookware, utensils, machine parts, vehicles, tanker trucks, vehiclewheels, work surfaces, tanks, immersion vessels, spray washers, andultrasonic baths. In addition, a detergent composition is providedaccording to the invention that can be used in environments other thaninside a dishwashing machine. Alkaline sensitive metals in need ofcleaning are found in several locations. Exemplary locations alsoinclude trucks, vehicle wheels, ware, and facilities. One exemplaryapplication of the alkaline sensitive metal cleaning detergentcomposition for cleaning alkaline sensitive metals can be found incleaning vehicle wheels in a vehicle washing facility. Compositionsincluding the novel corrosion inhibitor of the invention may be used inany of these applications and the like.

The invention also includes methods for cleaning aluminum and/oraluminum containing alloys by contacting the surface of the same withthe detergent/cleaning compositions of the invention. Thedetergent/cleaning compositions include a corrosion inhibiting amount ofone or more high molecular weight polyacrylates (or polyacrylic acidhomopolymers) having a molecular weight of at least about 5000.

The invention also includes methods for protecting aluminum and/oraluminum containing alloys from corrosion by use of the novel corrosioninhibiting composition of the invention. The method involves the step ofcontacting the surface of aluminum, or an aluminum containing alloy withthe corrosion inhibiting composition of the invention. The novelcorrosion inhibiting composition includes one or more high molecularweight polyacrylates (or polyacrylic acid homopolymers) having amolecular weight of at least about 5000.

Also included is a method for manufacturing a detergent composition. Themethod can include a step of adding a corrosion inhibitor comprising oneor more high molecular weight polyacrylates (or polyacrylic acidhomopolymers) having a molecular weight of at least about 5000 to adetergent composition. The corrosion inhibitor can be added to thedetergent composition when the detergent composition is a concentrateand/or when the detergent composition is a use solution.

DETAILED DESCRIPTION OF THE INVENTION

In this specification and the claims that follow, reference will be madeto a number of terms that shall be defined to have the followingmeanings:

The phrase “alkaline sensitive metal” identifies those metals thatexhibit corrosion and/or discoloration when exposed to an alkalinedetergent in solution. An alkaline solution is an aqueous solutionhaving a pH that is greater than 8 . Exemplary alkaline sensitive metalsinclude soft metals such as aluminum, nickel, tin, zinc, copper, brass,bronze, and mixtures thereof. Aluminum and aluminum alloys are commonalkaline sensitive metals that can be cleaned by the warewash detergentcompositions of the invention.

As used herein, weight percent (wt-%), percent by weight, % by weight,and the like are synonyms that refer to the concentration of a substanceas the weight of that substance divided by the total weight of thecomposition and multiplied by 100.

As used herein, the term “about” modifying the quantity of a componentor ingredient in the compositions of the invention or employed in themethods of the invention refers to variation in the numerical quantitythat can occur, for example, through typical measuring and liquidhandling procedures used for making concentrates or use solutions in thereal world; through inadvertent error in these procedures; throughdifferences in the manufacture, source, or purity of the ingredientsemployed to make the compositions or carry out the methods; and thelike. The term about also encompasses amounts that differ due todifferent equilibrium conditions for a composition resulting from aparticular initial mixture. Whether or not modified by the term “about,”the claims include equivalents to the quantities.

The term “surfactant” or “surface active agent” refers to an organicchemical that when added to a liquid changes the properties of thatliquid at a surface.

“Cleaning” means to perform or aid in soil removal, bleaching,de-scaling, de-staining, microbial population reduction, rinsing, orcombination thereof.

As used herein, the term “substantially free” refers to compositionscompletely lacking the component or having such a small amount of thecomponent that the component does not affect the performance of thecomposition. The component may be present as an impurity or as acontaminant and shall be less than 0.5 wt. %. In another embodiment, theamount of the component is less then 0.1 wt. % and in yet anotherembodiment, the amount of component is less than 0.01 wt. %.

As used herein, the term “ware” includes items such as eating andcooking utensils. As used herein, the term “warewashing” refers towashing, cleaning, or rinsing ware.

As used herein, a solid cleaning composition refers to a cleaningcomposition in the form of a solid such as a powder, a particle, anagglomerate, a flake, a granule, a pellet, a tablet, a lozenge, a puck,a briquette, a brick, a solid block, a unit dose, or another solid formknown to those of skill in the art. The term “solid” refers to the stateof the detergent composition under the expected conditions of storageand use of the solid detergent composition. In general, it is expectedthat the detergent composition will remain in solid form when exposed toelevated temperatures of 100° F. and preferably 120° F. A cast, pressed,or extruded “solid” may take any form including a block. When referringto a cast, pressed, or extruded solid it is meant that the hardenedcomposition will not flow perceptibly and will substantially retain itsshape under moderate stress, pressure, or mere gravity. For example, theshape of a mold when removed from the mold, the shape of an article asformed upon extrusion from an extruder, and the like. The degree ofhardness of the solid cast composition can range from that of a fusedsolid block, which is relatively dense and hard similar to concrete, toa consistency characterized as being malleable and sponge-like, similarto caulking material.

It should be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the content clearly dictates otherwise. Thus, for example,reference to a composition containing “a compound” includes a mixture oftwo or more compounds. It should also be noted that the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

The term “actives” or “percent actives” or “percent by weight actives”or “actives concentration” are used interchangeably herein and refers tothe concentration of those ingredients involved in cleaning expressed asa percentage minus inert ingredients such as water or salts.

As used herein, the terms “sodium tripolyphosphate-free” or “STPP-free”refers to a composition, mixture, or ingredients that do not containtripolyphosphates or to which the same has not been added. Should sodiumtripolyphosphate or—other phosphate containing compounds be presentthrough contamination of a composition, mixture, or ingredients, theamount of the same shall be less than 0.5 wt. %. In a preferredembodiment, the amount of the same is less than 0.1 wt. % and in a morepreferred embodiment, the amount is less than 0.01 wt. %.

The term “substantially similar cleaning performance” refers generallyto achievement by a substitute cleaning product or substitute cleaningsystem of generally the same degree (or at least not a significantlylesser degree) of cleanliness or with generally the same expenditure (orat least not a significantly lesser expenditure) of effort, or both.

Many articles having a surface that requires cleaning contain analkaline sensitive metal, such as, aluminum or aluminum containingalloys. Such articles can be found in industrial plants, maintenance andrepair services, manufacturing facilities, kitchens, and restaurants.Exemplary equipment having a surface containing an alkaline sensitivemetals include sinks, cookware, utensils, machine parts, vehicles,tanker trucks, vehicle wheels, work surfaces, tanks, immersion vessels,spray washers, and ultrasonic baths. In addition, a warewash detergentcomposition is provided according to the invention that can be used inenvironments other than inside a dishwashing machine. Alkaline sensitivemetals in need of cleaning are found in several locations. Exemplarylocations also include trucks, vehicle wheels, ware, and facilities. Oneexemplary application of the alkaline sensitive metal cleaning/warewashdetergent composition for cleaning alkaline sensitive metals can befound in cleaning vehicle wheels in a vehicle washing facility.Compositions of the invention may be used in any of these applications.

According to one embodiment of the invention a detergent composition isprovided comprising an alkaline source and a novel corrosion inhibitorcomprising one or more high molecular weight polyacrylates (orpolyacrylic acid homopolymers) having a molecular weight of at leastabout 5000.

The composition may also preferably include a detersive amount of asurfactant. The alkaline source can be provided in an amount effectiveto provide a use composition having a pH of at least about 8 . Thecorrosion inhibitor is provided in an amount sufficient to reducecorrosion of aluminum when the detergent composition is provided as ause composition for washing aluminum and aluminum containing alloys.

The detergent composition can be made available as multiple concentratesthat are diluted and combined at the situs of use to provide a usesolution for application to alkaline sensitive metals. An advantage ofproviding concentrates that are later combined is that shipping andstorage costs can be reduced because it can be less expensive to shipand store a concentrate rather than a use solution and is also moresustainable because less packaging is used. Although the detergentcomposition according to the invention can be provided as multipleconcentrates, it should be understood that the composition can beprovided as a ready to use solution. In addition, the multipleconcentrates can include two or more concentrates that are addedtogether. In addition, the concentrates can be provided in the form of aliquid solid, paste, gel, granulate, or powder.

The cleaning composition can be characterized as including an alkalinecomponent and a corrosion inhibitor component. The alkaline componentincludes a source of alkalinity. The source of alkalinity is provided sothat the use solution has a pH of at least 8.0 . The corrosion inhibitorcomponent includes a corrosion inhibitor of polyacrylic acid andpolymaleic acid homopolymers (or salts thereof). The corrosion inhibitorcomponent is provided for reducing corrosion of alkaline sensitivemetals by the use solution having a pH of at least 8.0.

A surfactant component may also be present. The surfactant componentprovides cleaning properties when used as part of the use solution at apH of at least 8.0 . A threshold inhibitor/crystal modifier can also beprovided to prevent calcium carbonate precipitation in a use solutionprovided at a pH in the range of 8.0 to 14.0 . Further additionalcomponents include the use of chelants as discussed hereinafter.

Source of Alkalinity

The source of alkalinity can be any source of alkalinity that iscompatible with the other components of the detergent composition andthat will provide a use solution with the desired pH. Exemplary sourcesof alkalinity include alkali metal hydroxides, alkali metal salts,silicates, phosphates, amines, and mixtures thereof. Exemplary alkalimetal hydroxides include sodium hydroxide, potassium hydroxide, andlithium hydroxide. The alkali metal hydroxide may be added to thecomposition in a variety of forms, including for example in the form ofsolid beads, dissolved in an aqueous solution, or a combination thereof.Alkali metal hydroxides are commercially available as a solid in theform of prilled solids or beads having a mix of particle sizes rangingfrom about 12-100 U.S. mesh, or as an aqueous solution, as for example,as a 45 wt. %, 50 wt. % and a 73 wt. % solution.

Exemplary alkali metal salts include sodium carbonate, trisodiumphosphate, potassium carbonate, and mixtures thereof. Exemplarysilicates include sodium metasilicates, sesquisilicates, orthosilicates,potassium silicates, and mixtures thereof. Exemplary phosphates includesodium pyrophosphate, potassium pyrophosphate, and mixtures thereof.Exemplary amines include alkanolamine. Exemplary alkanolamines includetriethanolamine, monoethanolamine, diethanolamine, and mixtures thereof.

The source of alkalinity is provided in an amount sufficient to providethe use solution with a pH of at least 8.0. The use solution pH range ispreferably between about 8.0 and about 13.0 , and more preferablybetween 10.0 to 12.5 . In general, the amount of alkalinity provided inthe concentrate can be in an amount of at least about 0.05 wt. % basedon the weight of the alkaline concentrate. The source of alkalinity inthe concentrate is preferably between about 0.05 wt. % and about 99 wt.%, more preferably is between about 0.1 wt. % and about 95 wt. %, andmost preferably is between 0.5 wt. % and 90 wt. %.

Corrosion Inhibitor Component

The invention comprises a novel corrosion inhibitor component of one ormore high molecular weight polyacrylates (or polyacrylic acidhomopolymers) having a molecular weight of at least about 5000 Thecorrosion inhibitor component effectively reduces corrosion to alkalinesensitive metals such as aluminum or aluminum containing alloys at a pHof about 8 or greater.

According to one embodiment of the present invention, one or more highmolecular weight polyacrylates are used as a corrosion inhibitor. Thepolyacrylate contains a polymerization unit derived from the monomerselected from the group consisting of acrylic acid, methacrylic acid,methyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, butyl acrylate, butyl methacrylate, iso-butyl acrylate,iso-butyl methacrylate, iso-octyl acrylate, iso-octyl methacrylate,cyclohexyl acrylate, cyclohexyl methacrylate, glycidyl acrylate,glycidyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate. and hydroxypropyl methacrylateand a mixture thereof, among which acrylic acid. methacrylic acid,methyl acrylate, methyl methacrylate, butyl acrylate, butylmethacrylate, iso-butyl acrylate, iso-butyl methacrylate, hydroxyethylacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate, and amixture thereof are preferred.

The above-mentioned acrylate monomers can be selected from the groupconsisting of methyl acrylate, methyl methacrylate, butyl acrylate,2-phenoxy ethyl acrylate, ethoxylated 2-phenoxy ethyl acrylate,2-(2-ethoxyethoxy)ethyl acrylate, cyclic trimethylolpropane formalacrylate, .beta.-carboxyethyl acrylate, lauryl(meth)acrylate, isooctylacrylate, stearyl(meth)acrylate, isodecyl acrylate,isoborny(meth)acrylate, benzyl acrylate, hydroxypivalyl hydroxypivalatediacrylate, ethoxylated 1,6-hexanediol diacrylate, dipropylene glycoldiacrylate, ethoxylated dipropylene glycol diacrylate, neopentyl glycoldiacrylate, propoxylated neopentyl glycol diacrylate, ethoxylatedbisphenol-A di(meth)acrylate, 2-methyl-1,3-propanediol diacrylate,ethoxylated 2-methyl-1,3-propanediol diacrylate,2-butyl-2-ethyl-1,3-propanediol diacrylate, ethylene glycoldimethacrylate, diethylene glycol dimethacrylate, 2-hydroxyethylmethacrylate phosphate, tris(2-hydroxy ethyl)isocyanurate triacrylate,pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate,propoxylated trimethylolpropane triacrylate, trimethylolpropanetrimethacrylate, pentaerythritol tetraacrylate, ethoxylatedpentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate,propoxylated pentaerythritol tetraacrylate, pentaerythritoltetraacrylate, dipentaerythritol hexaacrylate, (meth)acrylate,hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA),tripropylene glycol di(meth)acrylate1,4-butanediol di(meth)acrylate,1,6-hexanediol to di(meth)acrylate, allylated cyclohexyldi(meth)acrylate, isocyanurate di(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated glycerol tri(meth)acrylate,trimethylol propane tri(meth)acrylate, andtris(acryloxyethyl)isocyanurate, and a mixture thereof.

Polyacrylic acids, (C₃H₄O₂)_(n) or 2-Propenoic acid homopolymer; Acrylicacid polymer; Poly(acrylic acid); Propenoic acid polymer; PAA have thefollowing structural formula:

where n is any integer.

Examples of polyacrylates (polyacrylic homopolymers) which may be usedfor the invention and that are those with a molecular weight of at leastabout 5000 . One source of commercially available polyacrylates(polyacrylic homopolymers) useful for the invention includes the Acusol445 series from The Dow Chemical Company, Wilmington Del., USA. Thepolyacrylates (polyacrylic homopolymers) commercially available areAcusol 929 (10,000 MW) and Acumer 1510 (60,000 MW) both also availablefrom Dow Chemical. Yet another commercially available polyacrylic acidis AQUATREAT AR-6 (100,000 MW) from AkzoNobel Strawinskylaan 2555 1077ZZ Amsterdam Postbus 75730 1070 AS Amsterdam. Other suitablepolyacrylates (polyacrylic homopolymers) for use in the inventioninclude, can be obtained from suppliers such as Aldrich Chemicals,Milwaukee, Wis., and ACROS Organics and Fine Chemicals, Pittsburgh, Pa.

The corrosion inhibitor component can be provided in the corrosioninhibitor concentrate in an amount sufficient to provide a desired levelof corrosion inhibition when used in the use solution. There should besufficient amount of corrosion inhibitor to provide the desiredcorrosion inhibiting affect. It is expected that the upper limit on thecorrosion inhibitor component will be controlled by solubility. Thecorrosion inhibitor component can be provided in the corrosion inhibitorconcentrate in an amount of at least about 0.005 wt. %. It is preferredthat the corrosion inhibitor component be provided in the concentrate inan amount of between about 0. 5 wt. % and about 50 wt. %, morepreferably between about 1 wt. % and about 30 wt. %, and most preferablybetween 5% and 15% active polymer.

As further provided herein, additional corrosion inhibitors may also beadded to the detergent/cleaning compositions of the invention.

Cleaning Agent/Surfactant

The detergent composition can include at least one cleaning agentcomprising a surfactant or surfactant system. A variety of surfactantscan be used in a warewashing composition, such as anionic, nonionic,cationic, and zwitterionic surfactants. It should be understood thatsurfactants are an optional component of the detergent composition andcan be excluded. The detergent composition, when provided as aconcentrate, can include the cleaning agent in a range of between about0.5 wt. % and about 20 wt. %, more preferably in a range between about 1wt. % and 10 wt. %, and most preferably in a range between about 1.5 wt.% and 5 wt. %. Additional exemplary ranges of surfactant in aconcentrate include about 0.05 wt. % to 7.5 wt. %, more preferably about0.5 wt. % to 5 wt. %, and most preferably about 1 wt. % to 3 wt. %.

Exemplary surfactants that can be used are commercially available from anumber of sources. For a discussion of surfactants, see Kirk-Othmer,Encyclopedia of Chemical Technology, Third Edition, volume 8, pages900-912. When the composition includes a cleaning agent, the cleaningagent can be provided in an amount effective to provide a desired levelof cleaning.

Anionic surfactants useful detergent compositions include, for example,carboxylates such as alkylcarboxylates (carboxylic acid salts) andpolyalkoxycarboxylates, alcohol ethoxylate carboxylates, nonylphenolethoxylate carboxylates, and the like; sulfonates such asalkylsulfonates, alkylbenzenesulfonates, alkylarylsulfonates, sulfonatedfatty acid esters, and the like; sulfates such as sulfated alcohols,sulfated alcohol ethoxylates, sulfated alkylphenols, alkylsulfates,sulfosuccinates, alkylether sulfates, and the like; and phosphate esterssuch as alkylphosphate esters, and the like. Exemplary anionicsurfactants include sodium alkylarylsulfonate, alpha-olefinsulfonate,and fatty alcohol sulfates.

Nonionic surfactants useful in the detergent composition include, forexample, those having a polyalkylene oxide polymer as a portion of thesurfactant molecule. Such nonionic surfactants include, for example,chlorine-, benzyl-, methyl-, ethyl-, propyl-, butyl- and other likealkyl-capped polyethylene glycol ethers of fatty alcohols; polyalkyleneoxide free nonionics such as alkyl polyglycosides; sorbitan and sucroseesters and their ethoxylates; alkoxylated ethylene diamine; alcoholalkoxylates such as alcohol ethoxylate propoxylates, alcoholpropoxylates, alcohol propoxylate ethoxylate propoxylates, alcoholethoxylate butoxylates, and the like; nonylphenol ethoxylate,polyoxyethylene glycol ethers and the like; carboxylic acid esters suchas glycerol esters, polyoxyethylene esters, ethoxylated and glycolesters of fatty acids, and the like; carboxylic amides such asdiethanolamine condensates, monoalkanolamine condensates,polyoxyethylene fatty acid amides, and the like; and polyalkylene oxideblock copolymers including an ethylene oxide/propylene oxide blockcopolymer such as those commercially available under the trademarkPLURONIC® (BASF-Wyandotte), and the like; and other like nonioniccompounds. Silicone surfactants such as the ABIL® B8852 can also beused.

Cationic surfactants that can be used in the detergent compositioninclude amines such as primary, secondary and tertiary monoamines withC₁₋₈ alkyl or alkenyl chains, ethoxylated alkylamines, alkoxylates ofethylenediamine, imidazoles such as a 1-(2-hydroxyethyl)-2-imidazoline,a 2-alkyl-1-(2-hydroxyethyl)-2-imidazoline, and the like; and quaternaryammonium salts, as for example, alkylquaternary ammonium chloridesurfactants such as n-alkyl(C₁₂-C₁₈)dimethylbenzyl ammonium chloride,n-tetradecyldimethylbenzylammonium chloride monohydrate, anaphthylene-substituted quaternary ammonium chloride such asdimethyl-1-naphthylmethylammonium chloride, and the like. The cationicsurfactant can be used to provide sanitizing properties.

Zwitterionic surfactants that can be used in the detergent compositioninclude betaines, imidazolines, and propinates. If the detergentcomposition is intended to be used in an automatic dishwashing orwarewashing machine, the surfactants selected, if any surfactant isused, can be those that provide an acceptable level of foaming. Itshould be understood that warewashing compositions for use in automaticdishwashing or warewashing machines are generally considered to below-foaming compositions.

The surfactant can be selected to provide low foaming properties. Onewould understand that low foaming surfactants that provide the desiredlevel of detersive activity are advantageous in an environment such as adishwashing machine where the presence of large amounts of foaming canbe problematic. In addition to selecting low foaming surfactants, onewould understand that defoaming agents can be utilized to reduce thegeneration of foam. Accordingly, surfactants that are considered lowfoaming surfactants as well as other surfactants can be used in thedetergent composition and the level of foaming can be controlled by theaddition of a defoaming agent.

Threshold Agent/Crystal Modifier Component

The detergent composition may also include a threshold agent or crystalmodifier. for reducing precipitation of calcium carbonate in the usesolution. In general, it is expected that the threshold agent/crystalmodifier component will loosely hold calcium to reduce precipitation ofcalcium carbonate once it is subjected to a pH of at least 8.0.

Exemplary threshold agents/crystal modifiers include phosphonocarboxylicacids, phosphonates, phosphates, chelants, polymers, and mixturesthereof. Exemplary phosphonocarboxylic acids include those availableunder the name Bayhibit™ AM from Bayer, and include2-phosphonobutane-1,2,4, tricarboxylic acid (PBTC). Exemplaryphosphonates include amino tri(methylene phosphonic acid), 1-hydroxyethylidene 1-1-diphosphonic acid, ethylene diamine tetra(methylenephosphonic acid), hexamethylene diamine tetra(methylene phosphonicacid), diethylene triamine penta(methylene phosphonic acid), andmixtures thereof. Exemplary phosphonates are available under the nameDequest™ from Monsanto. Exemplary polymers include polyacrylates,polymethacrylates, polyacrylic acid, polyitaconic acid, polymaleic acid,sulfonated polymers, copolymers and mixtures thereof. It should beunderstood that the mixtures can include mixtures of different acidsubstituted polymers within the same general class. In addition, itshould be understood that salts of acid substituted polymers can beused. The useful carboxylated polymers may be generically categorized aswater-soluble carboxylic acid polymers such as polyacrylic andpolymethacrylic acids or vinyl addition polymers. Of the vinyl additionpolymers contemplated, maleic anhydride copolymers as with vinylacetate, styrene, ethylene, isobutylene, acrylic acid and vinyl ethersare examples. The polymers tend to be water-soluble or at leastcolloidally dispersible in water. The molecular weight of these polymersmay vary over a broad range although it is preferred to use polymershaving average molecular weights ranging between 1,000 up to 1,000,000,more preferably a molecular weight of 100,000 or less, and mostpreferably a molecular weight between 1,000 and 10,000.

The polymers or copolymers (either the acid-substituted polymers orother added polymers) may be prepared by either addition or hydrolytictechniques. Thus, maleic anhydride copolymers are prepared by theaddition polymerization of maleic anhydride and another comonomer suchas styrene. The low molecular weight acrylic acid polymers may beprepared by addition polymerization of acrylic acid or its salts eitherwith itself or other vinyl comonomers. Alternatively, such polymers maybe prepared by the alkaline hydrolysis of low molecular weightacrylonitrile homopolymers or copolymers. For such a preparativetechnique see Newman U.S. Pat. No. 3,419,502.

The threshold agent/crystal modifier component should be provided in anamount sufficient so that when it is in the use solution, itsufficiently disrupts crystal growth or prevents the precipitation ofcalcium carbonate and other insoluble salts such as magnesium silicate,magnesium hydroxide, and the like. In a preferred embodiment, thethreshold agent/crystal modifier component can be provided in a range ofabout 0.0001 wt. % to about 25 wt. %, and more preferably in a rangebetween about 0.001 wt. % and about 10 wt. %, and most preferablybetween about 0.01% and 8% based on the weight of the concentrate. Itshould be understood that the polymers, phosphonocarboxylates, andphosphonates can be used alone or in combination.

Hydrotrope Component

A hydrotrope component can be used to help stabilize the surfactantcomponent. It should be understood that the hydrotrope component isoptional and can be omitted if it is not needed for stabilizing thesurfactant component. In many cases, it is expected that the hydrotropecomponent will be present to help stabilize the surfactant component.Examples of the hydrotropes include the sodium, potassium, ammonium andalkanol ammonium salts of xylene, toluene, ethylbenzoate,isopropylbenzene, naphthalene, alkyl naphthalene sulfonates, phosphateesters of alkoxylated alkyl phenols, phosphate esters of alkoxylatedalcohols, short chain (C₈ or less) alkyl polyglycoside, sodium,potassium and ammonium salts of the alkyl sarcosinates, salts of cumenesulfonates, amino propionates, diphenyl oxides, and disulfonates. Thehydrotropes are useful in maintaining the organic materials, includingthe surfactant, readily dispersed in the cleaning composition and/oraqueous cleaning solution.

Additional Corrosion Inhibitors

Additional corrosion inhibitors which may be optionally added to thedetergent compositions of this invention include magnesium and/or zinc.Preferably, the metal ions are provided in water soluble form. Examplesof useful water soluble forms of magnesium and zinc ions are the watersoluble salts thereof including the chlorides, nitrates and sulfates ofthe respective metals. If any of the alkalinity providing agents are thealkali metal carbonates, bicarbonates or mixtures of such agents,magnesium oxide can be used to provide the Mg ion. The magnesium oxideis water soluble in such solutions and is a preferred source of Mg ions.In order to maintain the dispersibility of the magnesium and/or zinccorrosion inhibitors in aqueous solution, and in the presence of agentswhich would otherwise cause precipitation of the zinc or magnesium ions,e.g., carbonates, phosphates, etc., it might be advantageous to includea carboxylated polymer to the solution.

Other Additives

The detergent composition can include other additives such aschelating/sequestering agents, bleaching agents, detergent builders orfillers, hardening agents or solubility modifiers, defoamers,anti-redeposition agents, threshold agents, stabilizers, dispersants,enzymes, aesthetic enhancing agents (i.e., dye, perfume), and the like.Adjuvants and other additive ingredients will vary according to the typeof composition being manufactured. It should be understood that theseadditives are optional and need not be included in the cleaningcomposition. When they are included, they can be included in an amountthat provides for the effectiveness of the particular type of component.

Water conditioning polymers can also be used as a form of builder.Exemplary water conditioning polymers include polycarboxylates.Exemplary polycarboxylates that can be used as builders and/or waterconditioning polymers include those having pendant carboxylate (—CO₂.⁻)groups and include, for example, polyacrylic acid, maleic/olefincopolymer, acrylic/maleic copolymer, polymethacrylic acid, acrylicacid-methacrylic acid copolymers, hydrolyzed polyacrylamide, hydrolyzedpolymethacrylamide, hydrolyzed polyamide-methacrylamide copolymers,hydrolyzed polyacrylonitrile, hydrolyzed polymethacrylonitrile,hydrolyzed acrylonitrile-methacrylonitrile copolymers, and the like. Fora further discussion of chelating agents/sequestrants, see Kirk-Othmer,Encyclopedia of Chemical Technology, Third Edition, volume 5, pages339-366 and volume 23, pages 319-320, the disclosure of which isincorporated by reference herein.

Bleaching agents for use in a cleaning compositions for lightening orwhitening a substrate, include bleaching compounds capable of liberatingan active halogen species, such as Cl₂, Br₂, —OCL and/or —OBr⁻, underconditions typically encountered during the cleansing process. Suitablebleaching agents for use in the present cleaning compositions include,for example, chlorine-containing compounds such as chlorine,hypochlorite, and/or chloramine. Exemplary halogen-releasing compoundsinclude the alkali metal dichloroisocyanurates, chlorinated trisodiumphosphate, the alkali metal hypochlorites, monochloramine anddichloramine, and the like. Encapsulated chlorine sources may also beused to enhance the stability of the chlorine source in the composition(see, for example, U.S. Pat. Nos. 4,618,914 and 4,830,773, thedisclosure of which is incorporated by reference herein). A bleachingagent may also be a peroxygen or active oxygen source such as hydrogenperoxide, perborates, sodium carbonate peroxyhydrate, phosphateperoxyhydrates, potassium permonosulfate, and sodium perborate mono andtetrahydrate, with and without activators such as tetraacetylethylenediamine, and the like. The composition can include an effective amountof a bleaching agent. In a preferred embodiment when the concentrateincludes a bleaching agent, it can be included in an amount of about 0.1wt. % to about 60 wt. %, more preferably between about 1 wt. % and about20 wt. %, and most preferably between about 3 wt. % and about 8 wt. %.

The composition can include an effective amount of detergent fillers,which does not perform as a cleaning agent per se, but cooperates withthe cleaning agent to enhance the overall cleaning capacity of thecomposition. Examples of detergent fillers suitable for use in thepresent cleaning compositions include sodium sulfate, sodium chloride,starch, sugars, C₁-C₁₀alkylene glycols such as propylene glycol, and thelike. When the concentrate includes a detergent filler, it can beincluded an amount of about 1 wt. % to about 20 wt. % and between about3 wt. % to about 15 wt. %.

A defoaming agent for reducing the stability of foam may also beincluded in the composition to reduce foaming. When the concentrateincludes a defoaming agent, the defoaming agent can be provided in anamount of between about 0.01 wt. % and about 3 wt. %.

Examples of defoaming agents that can be used in the compositionincludes ethylene oxide/propylene block copolymers silicone compoundssuch as silica dispersed in polydimethylsiloxane, polydimethylsiloxane,and functionalized polydimethylsiloxane such as those available underthe name Abil B9952, fatty amides, hydrocarbon waxes, fatty acids, fattyesters, fatty alcohols, fatty acid soaps, ethoxylates, mineral oils,polyethylene glycol esters, alkyl phosphate esters such as monostearylphosphate, and the like. A discussion of defoaming agents may be found,for example, in U.S. Pat. No. 3,048,548 to Martin et al., U.S. Pat. No.3,334,147 to Brunelle et al., and U.S. Pat. No. 3,442,242 to Rue et al.,the disclosures of which are incorporated by reference herein.

The composition can include an anti-redeposition agent for facilitatingsustained suspension of soils in a cleaning solution and preventing theremoved soils from being redeposited onto the substrate being cleaned.Examples of suitable anti-redeposition agents include fatty acid amides,fluorocarbon surfactants, complex phosphate esters, styrene maleicanhydride copolymers, and cellulosic derivatives such as hydroxyethylcellulose, hydroxypropyl cellulose, and the like. In a preferredembodiment, the anti-redeposition agent, when included in theconcentrate, is added in an amount between about 0.5 wt. % and about 10wt. %, and more preferably between about 1 wt. % and about 5 wt. %.

Stabilizing agents that can be used include primary aliphatic amines,betaines, borate, calcium ions, sodium citrate, citric acid, sodiumformate, glycerine, maleonic acid, organic diacids, polyols, propyleneglycol, and mixtures thereof. The concentrate need not include astabilizing agent, but when the concentrate includes a stabilizingagent, it can be included in an amount that provides the desired levelof stability of the concentrate. In a preferred embodiment the amount ofstabilizing agent is about 0 to about 20 wt. %, more preferably about0.5 wt. % to about 15 wt. %, and most preferably about 2 wt. % to about10 wt. %.

Dispersants that can be used in the composition include maleicacid/olefin copolymers, polyacrylic acid, and mixtures thereof. Theconcentrate need not include a dispersant, but when a dispersant isincluded it can be included in an amount that provides the desireddispersant properties. Exemplary ranges of the dispersant in theconcentrate can be between about 0 and about 20 wt. %, more preferablybetween about 0.5 wt. % and about 15 wt. %, and most preferably betweenabout 2 wt. % and about 9 wt. %.

Enzymes can be included in the composition to aid in soil removal ofrobust soils such as starch, protein, and the like. Exemplary types ofenzymes include proteases, alpha-amylases, and mixtures thereof.Exemplary proteases that can be used include those derived from Bacilluslicheniformix, Bacillus lenus, Bacillus alcalophilus, and Bacillusamyloliquefacins. Exemplary alpha-amylases include Bacillus subtilis,Bacillus amyloliquefaceins and Bacillus licheniformis. The concentrateneed not include an enzyme. When the concentrate includes an enzyme, itcan be included in an amount that provides the desired enzymaticactivity when the warewashing composition is provided as a usecomposition. Exemplary ranges of the enzyme in the concentrate includebetween about 0 and about 15 wt. %,more preferably between about 0.5 wt.% and about 10 wt. %, and most preferably between about 1 wt. % andabout 5 wt. %.

In addition to providing alkalinity and having anti-redepositionproperties silicates can also provide further metal protection.Exemplary silicates include sodium silicate and potassium silicate. Thedetergent composition can be provided without silicates, but whensilicates are included, they can be included in amounts that provide fordesired metal protection. The concentrate can include silicates in arange between about 10 wt. % and about 80 wt. %, more preferably betweenabout 30 wt. % and about 70 wt. %, and most preferably between about 40wt. % and 60 wt. %.

The concentrate can include water. In general, it is expected that watermay be present as a processing aid and may be removed or become water ofhydration. It is expected that water may be present in both the liquidconcentrate and in the solid concentrate. In the case of the liquidconcentrate, it is expected that water will be present in a range ofbetween about 5 wt. % and about 95 wt. %, more preferably between about20 wt. % and about 75 wt. %, and most preferably between about 30 wt. %and about 50 wt. %. In the case of a solid concentrate, it is expectedthat the water will be present in ranges between about 5 wt. % and about60 wt. %, more preferably between about 15 wt. % and about 45 wt. %, andmost preferably between about 25 wt. % and about 40 wt. %. It should beadditionally appreciated that the water may be provided as deionizedwater or as softened water.

Various dyes, odorants including perfumes, and other aesthetic enhancingagents can be included in the composition. Dyes may be included to alterthe appearance of the composition, as for example, Direct Blue 86(Miles), Fastusol Blue (Mobay Chemical Corp.), Acid Orange 7 (AmericanCyanamid), Basic Violet 10 (Sandoz), Acid Yellow 23 (GAF), Acid Yellow17 (Sigma Chemical), Sap Green (Keystone Analine and Chemical), MetanilYellow (Keystone Analine and Chemical), Acid Blue 9 (Hilton Davis),Sandolan Blue/Acid Blue 182 (Sandoz), Hisol Fast Red (Capitol Color andChemical), Fluorescein (Capitol Color and Chemical), Acid Green 25(Ciba-Geigy), and the like.

Fragrances or perfumes that may be included in the compositions include,for example, terpenoids such as citronellol, aldehydes such as amylcinnamaldehyde, a jasmine such as C1S-jasmine or jasmal, vanillin, andthe like.

When the components that are processed to form the detergent areprocessed into a block, it is expected that the components can beprocessed by extrusion, casting, or pressed solid techniques. Ingeneral, when the components are processed by extrusion techniques, itis believed that the composition can include a relatively smaller amountof water as an aid for processing compared with the casting techniques.In general, when preparing the solid by extrusion, it is expected thatthe composition can contain between about 2 wt. % and about 10 wt. %water. When preparing the solid by casting, it is expected that theamount of water can be provided in an amount between about 20 wt. % andabout 50 wt. %.

The detergents of the invention may exist in a use solution orconcentrated solution that is in any form including liquid, free flowinggranular form, powder, gel, paste, solids, slurry, and foam. Thecleaning solutions are suitable to treat any metal surface contaminatedwith a wide variety of contaminants. Exemplary contaminants includegrease, clay, dirt, and oxide by-products. The present solutions may beused by contacting the contaminated metal parts with an effective amountof the aqueous solution. Preferred contact methods include immersion orsome type of impingement in which the cleaning solution is circulated orcontinuously agitated against the metal part or is sprayed thereon.Alternatively, agitation can be provided as ultrasonic waves. Thepresent invention is also suitable for clean-in-place operations that donot require disassembly of equipment.

The warewash detergents of this invention may be used at anytemperature, including an elevated temperature of about 90-180° F.

The various forms of the warewashing composition concentrate can beprovided in a water soluble packaging film. That is, solids and liquidscan be packaged in the water soluble films. Exemplary solids that can bepackaged in a water soluble film include powders, pellets, tablets, andblocks. Exemplary liquids that can be packaged in the water soluble filminclude gels and pastes.

The warewashing composition can be provided in the form of a solid.Exemplary solid dishwashing compositions are disclosed in U.S. Pat. No.6,410,495 to Lentsch et al., U.S. Pat. No. 6,369,021 to Man et al., U.S.Pat. No. 6,258,765 to Wei et al, U.S. Pat. No. 6,177,392 to Lentsch etal., U.S. Pat. No. 6,164,296 to Lentsch et al., U.S. Pat. No. 6,156,715to Lentsch et al., and U.S. Pat. No. 6,150,624 to Lentsch et al. Thecompositions of each of these patents are incorporated herein byreference.

Hard water is often characterized as water containing a total dissolvedsolids (TDS) content in excess of 200 ppm. This type of water is oftenreferred to as high solids containing water. In certain localities, thewater contains a total dissolved solids content in excess of 400 ppm,and even in excess of 800 ppm. The dissolved solids refers to thepresence of calcium and magnesium. These components of hard water can beaddressed by softening and/or treating the water, using builders,threshold agents, crystal modifiers and/or sequestrants in the detergentcomposition. In the case of water softening, sodium is often used todisplace the calcium and magnesium. The warewashing composition caninclude builder and/or sequestrant to handle the calcium and therebyreduce its tendency to precipitate with the calcium carbonate.

The detergent composition can include an effective amount ofanti-etching agent to prevent corrosion to glassware. The calcium thatis available in a use composition for precipitating with the aluminumion can be referred to as “free calcium ion” and is generally consideredto be the unchelated calcium ion in the use composition. When the levelof free calcium ion is relatively small, it is believed that the weightratio of the zinc ion to the aluminum ion can be provided at levels thatprovides the desired corrosion resistances exhibited by a lack ofetching. Because the presence of free calcium ion is not a particularconcern, it is believed that filming caused by precipitation of calciumion and aluminum ion will not be very significant. As a result, theratio of the zinc ion to the aluminum ion can be selected as describedin U.S. application Ser. No. 10/612,474 that was filed with the UnitedStates Patent and Trademark Office on Jul. 2, 2003, and which isincorporated herein by reference in its entirety. By way of example, theweight ratio of the zinc ion to the aluminum ion can be provided in arange of between about 20:1 to about 1:6, more preferably with a weightratio of the zinc ion to the aluminum ion in a range of between about15:1 and about 1:2. In situations where the free calcium ion isavailable in the use composition at a level sufficient to causeprecipitation of the calcium ion and the aluminum ion to provide visiblefilming, the ratio of the zinc ion to the aluminum ion can be controlledto provide resistance to etching and also resistance to visible filmingfrom precipitation of the calcium ion and the aluminum ion. For example,when the use composition contains in excess of 200 ppm free calcium ion,the weight ratio of the zinc ion to the aluminum ion can be provided atgreater than 2:1. By way of an exemplary range, it is believed that theweight ratio of the zinc ion to the aluminum ion can be provided in arange between about 20:1 and about 2:1, more preferably the weight ratioof zinc ion to aluminum ion can be greater than about 3:1, and mostpreferably can be provided in a range between about 15:1 and about 3:1.In addition, the weight ratio of zinc ion to aluminum ion can beprovided at greater than about 4:1 and can be provided at greater thanabout 6:1. It should be understood that the ratio of zinc ion toaluminum ion may exceed 15:1 and 20:1 when corrosion resistance canstill be provided. Furthermore, it should be understood that thereference to the weight ratio of the zinc ion and the aluminum ionrefers to a weight ratio based upon the zinc component of the zinc ionand the aluminum component of the aluminum ion. That is, it is theweight of the metal that is determined for purposes of the weight ratiorather than the weight of the entire molecule that may contain themetal. For example, in the case of sodium aluminate, the weight of thealuminum ion refers to the aluminum component of the molecule ratherthan the entire aluminate ion.

Formulating the Detergent Composition

The detergent composition can be formulated to handle the expectedcorrosion in a given environment. That is, the concentration of thecorrosion inhibitor can be adjusted depending upon several factors atthe situs of use including, for example, water hardness, food soilconcentration, alkalinity and the like. In machine warewashingapplications, a soil concentration of about 25 grams per gallon or moreis considered high, a concentration of about 15 to about 24 grams pergallon is considered medium, and a concentration of about 14 grams pergallon or less is considered low. Also, water hardness exhibiting 15grains per gallon or more is considered high, about 6 to about 14 grainsper gallon is considered medium, and about 5 grains per gallon or lessis considered low. In a use composition, an alkalinity of about 300 ppmor higher is considered high, an alkalinity of about 200 ppm to about300 ppm is considered medium, and an alkalinity of about 200 ppm or lessis considered low. In a use composition, a builder concentration ofabout 300 ppm or more is considered high, a builder concentration ofabout 150 ppm to about 300 ppm is considered medium, and a builderconcentration of 150 ppm or less is considered low.

Based on the desired minimum concentration of the corrosion inhibitor inthe use composition, the amount of the corrosion inhibitor in theconcentrate can be calculated knowing the solids content of the usecomposition and the concentrate can be formulated to provide at leastthe desired level of corrosion protection.

Forming the Concentrate

The components can be mixed/blended, extruded, or cast to form a solidsuch as pellets, powders or blocks. Heat can be applied from an externalsource to facilitate processing of the mixture.

A mixing system provides for continuous mixing of the ingredients athigh shear to form a substantially homogeneous liquid or semi-solidmixture in which the ingredients are distributed throughout its mass.The mixing system includes means for mixing the ingredients to provideshear effective for maintaining the mixture at a flowable consistency,with a viscosity during processing of about 1,000-1,000,000 cP,preferably about 50,000-200,000 cP. The mixing system can be acontinuous flow mixer or a single or twin screw extruder apparatus.

The mixture can be processed at a temperature to maintain the physicaland chemical stability of the ingredients, such as at ambienttemperatures of about 20-80° C., and about 25-55° C. Although limitedexternal heat may be applied to the mixture, the temperature achieved bythe mixture may become elevated during processing due to friction,variances in ambient conditions, and/or by an exothermic reactionbetween ingredients. Optionally, the temperature of the mixture may beincreased, for example, at the inlets or outlets of the mixing system.

An ingredient may be in the form of a liquid or a solid such as a dryparticulate, and may be added to the mixture separately or as part of apremix with another ingredient, as for example, the corrosion inhibitorcomponent may be separate from the remainder of the detergent. One ormore premixes may be added to the mixture.

The ingredients are mixed to form a substantially homogeneousconsistency wherein the ingredients are distributed substantially evenlythroughout the mass. The mixture can be discharged from the mixingsystem through a die or other shaping means. The profiled extrudate canbe divided into useful sizes with a controlled mass. The extruded solidcan be packaged in film. The temperature of the mixture when dischargedfrom the mixing system can be sufficiently low to enable the mixture tobe cast or extruded directly into a packaging system without firstcooling the mixture. The time between extrusion discharge and packagingcan be adjusted to allow the hardening of the detergent block for betterhandling during further processing and packaging. The mixture at thepoint of discharge can be about 20-90° C., and about 25-55° C. Thecomposition can be allowed to harden to a solid form that may range froma low density, sponge-like, malleable, caulky consistency to a highdensity, fused solid, concrete-like block.

Optionally, heating and cooling devices may be mounted adjacent tomixing apparatus to apply or remove heat in order to obtain a desiredtemperature profile in the mixer. For example, an external source ofheat may be applied to one or more barrel sections of the mixer, such asthe ingredient inlet section, the final outlet section, and the like, toincrease fluidity of the mixture during processing. Preferably, thetemperature of the mixture during processing, including at the dischargeport, is maintained at about 20-90° C.

When processing of the ingredients is completed, the mixture may bedischarged from the mixer through a discharge die. The solidificationprocess may last anywhere from a few minutes to about six hours,depending, for example, on the size of the cast or extruded composition,the ingredients of the composition, the temperature of the composition,and other like factors. Preferably, the cast or extruded composition“sets up” or begins to harden to a solid form within about 1 minute toabout 6 hours, more preferably within about 1 minute to about 3 hours,and most preferably within about 1 minute to about 1.0 hours.

The concentrate can be provided in the form of a liquid. Various liquidforms include gels and pastes. Of course, when the concentrate isprovided in the form of a liquid, it is not necessary to harden thecomposition to form a solid. In fact, it is expected that the amount ofwater in the composition will be sufficient to preclude solidification.In addition, dispersants and other components can be incorporated intothe concentrate in order to maintain a desired distribution ofcomponents.

The packaging receptacle or container may be rigid or flexible, andcomposed of any material suitable for containing the compositionsproduced according to the invention, as for example glass, metal,plastic film or sheet, cardboard, cardboard composites, paper, and thelike. The composition is processed at around 150-170° F. and aregenerally cooled to 100-150° before packaging allowing the mixture to bedirectly added to the container or other packaging system withoutstructurally damaging the receptacle. As a result, a wider variety ofmaterials may be used as packaging systems.

The packaging material can be provided as a water soluble packagingmaterial such as a water soluble packaging film. Exemplary water solublepackaging films are disclosed in U.S. Pat. Nos. 6,503,879; 6,228,825;6,303,553; 6,475,977; and 6,632,785, the disclosures of which areincorporated herein by reference. An exemplary water soluble polymerthat can provide a packaging material that can be used to package theconcentrate includes polyvinyl alcohol. The packaged concentrate can beprovided as unit dose packages or multiple dose packages. In the case ofunit dose packages, it is expected that a single packaged unit will beplaced in the cleaning apparatus, such as the detergent compartment ofthe dishwashing machine, and will be used up during a single wash cycle.In the case of a multiple dose package, it is expected that the unitwill be placed in a hopper and a stream of water will erode a surface ofthe concentrate to provide a liquid concentrate that will be introducedinto the dishwashing machine.

While the invention is described in the context of a warewashingcomposition for washing articles in an automatic dishwashing machine, itshould be understood that the composition can be used for washingnon-ware items. That is, the composition can be referred to as acleaning composition and can be used to clean various items and, inparticular, items that may suffer from corrosion and/or etching. Itshould be understood that because the detergent is intended to be usedin an automatic dishwashing machine certain components can be excludedfrom the detergent compositions not intended for use in warewashmachines, and vice versa. For example, surfactants that generate a lotof foam may be used in a cleaning composition not intended for use in anautomatic dishwashing machine.

Exemplary ranges of the detergent composition in its simplest forminclude a source of alkalinity and a corrosion inhibitor. It ispreferred that the source of alkalinity comprises a range of 30-99wt. %,more preferably a range of 35-80wt. % and most preferably a range of40-70%. The corrosion inhibitor of the invention is present in apreferred range of 1-30 wt. %, a more preferred range of 5-25wt. % and amost preferred range of 10 to 20 wt. % of active polymer.

According to the invention, the corrosion inhibitor comprises one ormore high molecular weight polyacrylates (polyacrylic homopolymers)having a molecular weight of at least about 5000.

Exemplary ranges for typical components of detergent compositionsincluding the corrosion inhibitor of the invention are shown in tables 1and 2 . Exemplary ranges when provided as a gel or a paste are shown inTable 1. Exemplary ranges for components of the detergent compositionwhen provided as a solid are shown in Table 2.

TABLE 1 Gel or Paste Detergent Composition (wt. %) Component FirstExemplary Second Exemplary Third Exemplary Water 5-95 20-75  30-50Silicate/ 0-65 25-60  35-55 alkaline source Builder 0-30 3-20  6-15Stabilizer 0-20 0.5-15    2-10 Dispersant 0-20 0.5-15   2-9 Enzyme 0-150.5-10   1-5 Polyacrylate 0.5-50   1-30  5-20 Corrosion InhibitorSurfactant 0.5-15   1-10 2-5 Fragrance 0-10 0.01-5    0.1-2   Dye 0-1 0.001-0.5    0.01-0.25

TABLE 2 Solid Detergent Composition (wt. %) Component First ExemplarySecond Exemplary Third Exemplary Water 5-60 15-45 25-40 Builder 0-6025-50 35-45 Silicate/ 0-65 25-60 35-55 alkaline source Dispersant 0-100.001-5    0.01-1   Enzyme 0-15  1-10 2-5 Polyacrylate- 0.5-50    1-30 5-20 Corrosion Inhibitor Surfactant 0.5-15    1-10 2-5 Fragrance 0-100.01-5   0.1-2   Dye 0-1  0.001-0.5  0.01-0.25

The above specification provides a basis for understanding the broadmeets and bounds of the invention. The following examples and test dataprovide an understanding of certain specific embodiments of theinvention. The examples are not meant to limit the scope of theinvention that has been set forth in the foregoing description.Variations within the concepts of the invention are apparent to thoseskilled in the art.

EXAMPLES Example 1

According to the invention, several detergent compositions were preparedwith high molecular weight polyacrylates (polyacrylic acid homopolymer)having a molecular weight of at least about 5000 as the corrosioninhibitor and compared to a commercially available control formulationcontaining sodium tripolyphosphate as a corrosion inhibitor. Thedetergent components were kept constant except for the corrosioninhibitor component. Commercially available high molecular weightpolyacrylates (polyacrylic acid homopolymer) having a molecular weightof at least about 5000 used in the 3 samples are listed below.

Acusol 929—10,000 MW polyacrylate, 45 % active

Acumer 1510—70,000 MW polyacrylate, 25 % active

Acusol 445ND—4,500 MW polyacrylate, 95-100% active

The components of the test detergents are listed in Tables A and Bbelow.

TABLE A Corrosion Inhibitor Component Corrosion Inhibitor CONTROL EXP1EXP2 EXP3 STPP 25 wt. % 0 0 0 PolyAcrylate Acusol 929 Acumer Acusol(45%) 1510 (25%) 445ND 22 wt. % 40 wt. % 10 wt. %

TABLE B Warewash detergent components CONTROL EXP1 EXP2 EXP3 Softened30.877 wt. % 24 wt. % 6 wt. % 36 wt. % water Source of  25.85 wt. % 53wt. % 53 wt. % 53 wt. % alkalinity Surfactant   .86 wt. %  1 wt. %  1wt. %  1 wt. %

The experimental detergent compositions and the control were testedaccording to standard protocol in a multi-cycle aluminum corrosioninhibition evaluation for warewash detergents as described hereinafter.

A 13″×9″ aluminum sheet pan was obtained by cutting a 13″×18″ pan inhalf. The pan was gently cleaned with warm soapy water and anon-abrasive sponge to ensure any foreign materials or residues fromcutting and storage were removed. Next a dishwasher was filled withwater and heaters were turned on. For high temperature machines, thewash temperature was set to 160° F. and the final rinse temperature wasadjusted to 180° F. The Machine was then primed with the desiredconcentration of detergent and the pan was placed in the second slotfrom front with the rim facing down and cut edge facing up.

The pan rack was then pushed into the machine, the door was closed, andthe cycle was started. At the beginning of each cycle, the appropriateamount of detergent was added to the wash tank to make up for the rinsedilution. This was repeated until the desired number of cycles werecompleted.

Results:

Pans were rated visually and photographed against a black background.The rating scale used was as follows and was the same for the front andback of each pan:

Rating Film 1 No corrosion or discoloration 2 Approximately 25% of thepan is discolored and/or corroded 3 Approximately 50% of the pan isdiscolored and/or corroded 4 Approximately 75% of the pan is discoloredand/or corroded 5 All or nearly all of the pan is heavily discoloredand/or corrodedThe results shown in the following table correlate to the compositionsshown above. Results are graded visually from 1 (best) to 5 (worst)depending upon the amount of blackening/corrosion of an aluminum pan.

Product Cycles Conc (ppm) Front Score Back Score SMP In-Line 50 2000 1 1SMP 1 50 975 1 1.5 SMP 2 50 975 1.5 1 SMP 3 50 975 5 5

As can be seen, the high molecular weight polyacrylates (acrylic acidhomopolymer) cleaned almost as well as the control, and are much moreenvironmentally friendly as the formulations contained to phosphorous.

As also can be seen the at molecular weights of under 5000, thecorrosion inhibition was unsatisfactory, thus the polyacrylate(polyacrylic acid homopolymer) should have a molecular weight of atleast about 5000 and preferably 10,000 or more.

What is claimed is:
 1. A detergent composition comprising: (a) analkaline source in an amount effective to provide a use compositionhaving a pH of at least about 8 and obtained by diluting the detergentcomposition with water; (b) a corrosion inhibitor component in an amountsufficient for reducing corrosion of aluminum or aluminum containingalloys, the corrosion inhibitor component comprising one or morepolyacrylic acid homopolymers having a molecular weight of at leastabout 5,000 daltons, wherein said sufficient amount of corrosioninhibitor is between 10 wt. % and 30 wt. %; (c) a fragrance and/or dye,wherein said fragrance is in an amount between about 0.01 wt. % to about5 wt. % and wherein said dye is in an amount between about 0.001 wt. %to about 0.5 wt. %; and (d) less than about 0.1 % by weight ofphosphorous, wherein said composition does not contain polymaleic acidpolymers, and wherein said composition does not include 1-hydroxyethylidene 1-1-diphosphonic acid.
 2. The detergent composition accordingto claim 1 further comprising: (e) a cleaning agent comprising adetersive amount of a surfactant.
 3. The detergent composition accordingto claim 2, wherein the detergent composition comprises between about0.5 wt. % and about 20 wt. % of the cleaning agent.
 4. The detergentcomposition according to claim 1, wherein the corrosion inhibitorcomponent comprises one or more polyacrylic acid homopolymers having amolecular weight of greater than 10,000 daltons.
 5. The detergentcomposition according to claim 4, wherein the corrosion inhibitorcomponent comprises one or more polyacrylic acid homopolymers having amolecular weight of greater than 50,000 daltons.
 6. The detergentcomposition according to claim 5, wherein the corrosion inhibitorcomponent comprises one or more polyacrylic acid homopolymers having amolecular weight of 70,000 daltons or greater.
 7. The detergentcomposition according to claim 5, wherein the corrosion inhibitorcomponent comprises one or more polyacrylic acid homopolymers having amolecular weight of 100,000 daltons or greater.
 8. The detergentcomposition according to claim 1, wherein the detergent compositioncomprises between about 10 wt. % and about 25 wt. % of active corrosioninhibitor component.
 9. The detergent composition according to claim 2,wherein the cleaning agent comprises at least one of an anionicsurfactant, a nonionic surfactant, a cationic surfactant, or azwitterionic surfactant.
 10. The detergent composition according toclaim 1, wherein the alkaline source comprises a metal silicate.
 11. Thedetergent composition according to claim 1 wherein the detergentcomprise less than about 0.05% by weight of phosphorous.
 12. Thedetergent composition according to claim 1 wherein the detergentcontains less than about 0.01% by weight of phosphorous.
 13. A methodfor manufacturing a detergent composition, the method comprising: (a)providing an amount of corrosion inhibitor in a detergent compositionconcentrate sufficient to provide a level of corrosion inhibitor in ause composition as a result of diluting the detergent concentrate withwater at a ratio of water to the detergent concentrate of at least about20:1, wherein said corrosion inhibitor comprises one or more polyacrylicacid homopolymers having a molecular weight of at least about 5,000daltons, wherein corrosion inhibitor is between 10 wt. % and 30 wt. % ofthe detergent composition, wherein said corrosion inhibitor containsless than about 0.1% by weight of phosphorous, wherein said detergentcomposition comprises a fragrance and/or dye, wherein said fragrance isin an amount between about 0.01 wt. % to about 5 wt. %, and wherein saiddye is in an amount between about 0.001 wt. % to about 0.5 wt. %,wherein said detergent composition does not include 1-hydroxy ethylidene1-1-diphosphonic acid, and wherein said detergent composition does notinclude polymaleic acid polymers.
 14. A method for protecting aluminumor aluminum containing alloys from corrosion comprising: contacting thesurface of the same with the detergent composition of claim
 1. 15. Themethod of claim 14, wherein the corrosion inhibitor comprises one ormore polyacrylic acid homopolymers having a molecular weight of greaterthan 10,000 daltons.
 16. The method of claim 14, wherein the corrosioninhibitor comprises one or more polyacrylic acid homopolymers having amolecular weight of greater than 50,000 daltons.
 17. The method of claim14, wherein the corrosion inhibitor comprises one or more polyacrylicacid homopolymers having a molecular weight of 70,000 daltons orgreater.